Air conditioner with selective filtering for air purification

ABSTRACT

A split air conditioner has a cabinet with a fan and evaporator for mounting within a structure. The cabinet includes a filter or a stacked filter system positioned in the flow path between an air inlet and an air outlet for filtering contaminants from the air. Movable dampers are provided for selectively changing the airflow path to selectively bypass the filter to provide a greater or lesser degree of filtration of the air. Preferably, the filter is a high performance HEPA-like filter having substantially less pressure drop .

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) and the benefitof U.S. Provisional Application Nos. 62/010,088 entitled SPLIT SYSTEMOUTDOOR AIR UNIT, filed on Jun. 10, 2014, by Nihat O. Cur and 62/064,181entitled SPLIT SYSTEM AIR CONDITIONER/HEAT PUMP WITH DUAL HUB FANCONDENSING UNIT AND ENHANCED COMPRESSOR COOLING, filed on Oct. 15, 2014,by Nihat O. Cur, et al., the entire disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a split system air conditioning systemin which an evaporator component is positioned within a structure and iscoupled to an external compressor/condenser unit and particularly to acabinet enclosure for an evaporator which includes supplemental airfiltration which can be selectively controlled by the user.

Split air conditioners are becoming popular for the use in individualareas of buildings, such as a bedroom or living room, where central airconditioning with universal duct work is either not available orunnecessary for living comfort. Split air conditioners typically includea wall-mounted indoor unit which includes an evaporator and a fan forcooling and dehumidifying air within a room. The indoor unit is coupledto an outdoor compressor/condenser unit for dissipating heat from thetypically wall-mounted system. Such systems provide cooling frequentlyfor a single room or multiple rooms, however, they do not providesubstantial air purification by filtering or the like other than asimple screen filter which is not effective for removal of mostpollutants.

Accordingly, it would be desirable to provide a split air conditionersystem in which air filtering can be achieved and controlled by the userto provide a selectable amount of air filtration depending upon, forexample, seasonal allergies to pollen or other allergens which may bepresent in the air and which it is desired to be filtered utilizing asplit air conditioning system.

SUMMARY OF THE INVENTION

The system of the present invention accommodates this need by providingan air conditioner having a cabinet for mounting to the indoor surfaceof a structure. Additionally, this air conditioning unit could be freestanding on the floor or surface. The cabinet includes a fan and anevaporator with an inlet for drawing untreated air into the cabinet, onone side of the evaporator, and an air outlet on the opposite side ofthe evaporator to provide conditioned air output from the cabinet.

In one embodiment of the invention, the cabinet includes a filterpositioned in the flow path between the air inlet and the outlet forfiltering contaminants from the air. In a preferred embodiment of theinvention, movable dampers are provided for selectively changing theairflow path to either bypass or partially bypass the filter to providea greater or lesser degree of filtration of the air. in the mostpreferred embodiment of the invention, the filter is a HEPA-performancelike filter but without the substantial flow resistance associated withHEPA filters on the order of 50% or better reduction in flow resistance.

These and other features, objects and advantages of the presentinvention will become apparent upon reading the following descriptionthereof together with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an air conditioning unitof the present invention, shown mounted in relationship to a wall forproviding filtered and conditioned air to a living space;

FIG. 1A is a front elevational view of the cabinet shown in FIG. 1;

FIGS. 2-7 are cross-sectional schematic views of air conditioning unitswith selective dampers for selectively controlling the airflow through afilter in the air conditioning unit;

FIGS. 8-10 are cross-sectional schematic views of an air conditioningunit employing a rotary damper for selectively controlling the airflowthrough a filter contained by the unit;

FIGS. 11-14 are top and front elevational views of alternativeembodiments of the invention, where air is exhausted throughspaced-apart air outlets on opposite edges of the cabinet;

FIGS. 15-25 illustrate top, perspective, and fragmentary exploded viewsof a filter system in which the filters can be pivotally moved betweenoperational positions where maximum filtering takes place to bypasspositions in which a selectable amount of filtering is available;

FIGS. 26-27 are top schematic views illustrating the movement of thefilters also seen in FIGS. 15-25;

FIGS. 28 and 29 are top schematic views illustrating another embodimentin which filters pivot on a vertical axis on outside edges of an airconditioning cabinet;

FIGS. 30 and 31 schematically illustrate in a top plan view a slidingfilter where, in FIG. 30, the filter is fully engaged for maximumfiltration and, in FIG. 31, the filter is moved away from the airconditioner cabinet to allow filtered and unfiltered air to enter thecabinet for increased cooling;

FIGS. 32 and 33 illustrate an alternative embodiment in a top plan andschematic view of a filter construction in which two filters both moveaway from the air conditioner cabinet and away from each other, asillustrated in FIG. 33, to allow filtered and unfiltered air to enterthe cabinet; and

FIG. 34 illustrates in a top plan schematic view a filter constructionwhich can be raised or rolled away, like a garage door, to vary theamount of filtration provided by the system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 1A illustrate one embodiment of the present invention, inwhich a split air conditioning system includes an indoor air conditionerunit 10 with a cabinet 12, which has a rear air inlet grill 14 forreceiving inlet air to be conditioned, as shown by arrows 15. Thecabinet 12 is mounted to a support wall 16 of a building structure usingsuitable brackets. Within cabinet 12, there is positioned a microchannel or a fin-and-tube type heat exchanger which is a flat evaporator20 conventionally coupled to an outside compressor/condenser unit forreceiving a high pressure refrigerant liquid through a capillary tube orexpansion valve fluidically coupled to the evaporator for cooling theinput air 15 flowing through the air conditioner cabinet 12. As onepossible illustration, three muffin-type fans 25 are mounted to thefront of the cabinet 12 facing the interior of the room for exhaustingtreated air in the direction indicated by arrows 17. The cabinet furtherincludes a filter unit 30 positioned between the inlet grill 14 and theevaporator 20 for purifying the air from contaminants, such as pollen,dust, and the like. In this embodiment of the invention, all of theinput air 15 is not only conditioned for cooling and removing humiditybut also filtered by the filter 30, which can provide close to HEPA-likeperformance but without the substantial pressure drop associated withHEPA filters. An example of such a filter could be 3M's HAF filter withionizer, or a stacked filter combination with multiple filters forvarious pollutants such as viruses, hydrocarbons or other volatileorganic compounds (VOC's), heavy metals, requiring filtration byactivated charcoal or like, or Darwin's ifD® technology, etc. Filters inthe system can be stacked in different combinations to createperformance characteristics. Carbon, high air flow, HEPA, dust filterscan be used in the air flow depending on the air characteristics needed.

In each of the embodiments described, the evaporator unit is coupled tothe outside compressor/condenser utilizing conventional refrigerantfluid conduits for interconnecting the units. Similarly, the indoorevaporator system may include a drain for removing condensate that mayhave been collected during the cooling process. Additionally, a standardgross particle filter covers the air inlet side of the evaporator at alltimes during operation. Naturally, suitable electrical controls andconnections are also provided. The schematic drawings illustrate themounting of the indoor cabinet to structural walls, although the unitscan likewise be attached to the ceiling of a building in a conventionalmanner, or may be of the floor standing type popular in Asian markets.

Turning now to FIGS. 2 and 3, there is shown the indoor air conditioningunit 40 of a split system. Unit 40 is mounted to the wall 42 of abuilding utilizing conventional upper and lower mounting brackets 44 and46. Unit 40 includes a cabinet 50 which typically will be an elongatedrectangular cabinet similar to cabinet 12 shown in FIG. 1A. In theembodiment shown in FIGS. 2 and 3, however, an elongated cross-flow fan52 is employed and is surrounded by upper and lower baffles 54 and 56 tofunnel incoming air through an air inlet grill 58 through a filter or afilter 60 and the evaporator 62 in a direction indicated by arrows A inFIGS. 2 and 3. The fan discharges the conditioned and filtered airoutwardly through outlet grill 53 adjacent the fan 52. The cabinet 50includes movable guillotine-type dampers 70 and 72 slideably mountedwithin the cabinet and movable between the closed position shown in FIG.2 and an open position as shown in FIG. 3. In the open position,supplemental air (indicated by arrows B in FIG. 3) can enter the cabinet50 on the downstream side of filter 60, thereby bypassing the filter 60to some extent. The guillotine dampers 70, 72 slideably fit alongchannels 71, 73 (FIG. 2) in cabinet 50 to selectively block or allow airin the direction of arrows B to bypass filter 60 and flow directlythrough the evaporator 62 depending upon the need for filtering incomingair, shown by arrows A in FIGS. 2 and 3. For such purpose, the mountingbrackets 44, 46 provide clearance for the input grill 58 in the backwall 57 of cabinet 50 to allow input airflow which flows through filter60 in both the FIGS. 2 and 3 configurations, although in the FIG. 3configuration, less of the air is filtered. The dampers 70, 72 can bemoved to positions intermediate that shown in FIGS. 2 and 3 toselectively control the amount of air that is filtered as desired. Theexit air shown by arrows C in FIG. 3 represents the conditioned andfiltered air drawn through the unit by fan 52.

FIGS. 4 and 5 have the same configuration as the units shown in FIGS. 2and 3 except aligned muffin-type fans 51, such as shown in FIG. 1A, areemployed as opposed to an elongated cross-flow fan 52. The remainingcomponents of the FIGS. 4 and 5 embodiment are the same and use the samereference numbers.

FIGS. 6 and 7 show a unit 40 of the same general construction as theFIGS. 2 and 3 embodiment but mounted to receive air from below the unit40 as opposed to from above as shown in FIGS. 2 and 3. Thus, theincoming air, represented by arrows A in FIG. 7, enters from the lowerside of the unit 40, which carries the same reference numbers as theFIGS. 2 and 3 embodiment.

FIGS. 8-10 disclose another embodiment of the present invention in whicha rotary damper 80 can be moved between three separate positionsproviding partially filtered air (FIG. 8), completely filtered air (FIG.9), and filtered air which is not cooled by the evaporator (FIG. 10).Referring initially to FIG. 8, those components similar to thecomponents shown in the previous figures employ the same referencenumbers. In FIG. 8, the rotary damper 80 is mounted to the lower end 59of an air inlet 58 in sealed rotatable engagement with the lower part ofcabinet 50 and baffle 56. The damper 80 has an open pathway at section81. Side 83 of the damper is enclosed and blocks airflow. In theposition shown in FIG. 8, incoming air (shown as arrow A) enters throughinlet grill 58 and flows through the filter 60 and evaporator 62 and isdischarged, as indicated by arrow C, as cooled air. Additional air,shown by arrow B, flows through the open pathway 81 of damper 80bypassing the filter 60 but flowing through the evaporator 62 and thencombines to form the mixed filtered and cooled output air indicated byarrows C.

In FIG. 9, the damper 80 is rotated clockwise about 90° and, inconnection with baffle 56, closes off the flow of air from inlet 59through the damper 80. In this position, all the incoming air A flowsboth through the filter 60 and the evaporator 62, and none of the airbypasses the filter.

In FIG. 10, the damper is moved to a position rotated approximately 180°from that shown in FIG. 9. A new pathway, shown by arrows D, for theflow of air through the open section 81 of damper 80 bypasses theevaporator 62 completely but only after it has been filtered by filter60. The remaining input air indicated by arrow A passes through both thefilter 60 and evaporator 62 and combines with the unchilled air, shownby arrow D, exiting as shown by arrow C, as partially chilled butentirely filtered air. Thus, with the embodiment shown in FIGS. 8-10,three different modes of operation are possible.

In another embodiment of the invention shown in FIGS. 11-14, there is anindoor air conditioning unit 90 which can have a filter and baffleconstruction as in the prior embodiments to selectively filter thedischarge air. In this embodiment, the inlet grill 92 receives air drawnthrough a filter and an evaporator into the center of centrifugal fan100. The unit 90 has a pair of vertically extending rectangular outletports 94 and 96 on opposite sides of the cabinet 50. Conditioned and/orselectively filtered air is, therefore, distributed on opposite sides ofthe centrifugal fan 100, as illustrated by arrows C.

In the embodiment shown in FIGS. 13 and 14, a pair of spaced-apartcentrifugal fans 102, 104 are employed to draw air into the cabinetthrough inlet grill 92. A pair of rectangular horizontally extendingoutlet ports 91 and 93 at the top and bottom of the cabinet 50 are nearopposed edges of the cabinet, and the conditioned and selectivelyfiltered air is exhausted, as shown by arrows C through outlet ports 91and 93. In these specific embodiments, the presence of a centrifugal fanwith higher pressure capabilities may allow the usage of higher pressuredrop filter media which can come close to HEPA filter performance.

The FIGS. 15-25 embodiment of the invention provides a cabinet enclosure110 for housing a fan 112 and an evaporator 114 with an air outlet 116from the cabinet 110. The cabinet includes a standard gross particlefilter 115 and a pair of movable filter assemblies 120 with theright-side filter assembly shown in detail, it being understood that theleft-side filter assembly is substantially identical only with the partsreversed. The filter assemblies 120, as best seen in FIGS. 15-25,include a rack and pinion drive mechanism 130 including a sliding rack132 movably supported on the cabinet walls 117 and 118 by the structure,as best seen in FIGS. 20-25. The rack 132 is driven by a meshing piniongear 134 which engages the teeth 137 of the rack 132. Gear 134 isrotatably driven by a vertically extending drive shaft 136 coupled to asuitable drive motor. The end 131 of rack 132 is pivotally coupled by aroller follower 129 (FIGS. 17-19) which rides in a slot 128 in the end131 of rack 132. Follower 129 is coupled to a pin 133 on filter 120 toallow pin 133 and follower 129 to ride in slot 128 as the filter 120 ismoved, as best seen in FIGS. 17 and 18. The filter 120 can be the sametype described above, namely, a 3M HAF filter. The filter 120 has theshape of a generally rectangular door-like panel with an edge oppositepivot pin 133 pivotally mounted to cabinet 110 at the top and bottom(only the top is shown, the bottom structure is substantially the same).The pivot connection to cabinet 110 includes a sliding pivot connectionincluding a pin 138 which, as best seen in FIGS. 17 and 18, has a rollerfollower 142 that slides in a slot 144 of a bracket 146 secured to theupper wall 117 of cabinet enclosure 110.

The rack 132 includes a slot 135 which rides under the pinion gear 134and is guided by a suitable bushing 139 (FIG. 23) mounted to drive shaft136, such that, as seen in FIG. 18, when the drive gear of the pinion134 rotates in a counterclockwise direction (as viewed from the top),the filter 120 is urged toward the open position shown in FIG. 17 by thepivot connection of the end of rack 132 to pivot pin 133 and pivot pin138. As the door-like filter panel 120 moves to an open position, thepivot pin 138 slides within the slot 144 of bracket 146 to extend theinward edge 121 of panel 120 to an outward position clearing the cabinetenclosure 110 and allowing air to bypass the filter panel 120 and movein the direction indicated by arrow A in FIG. 17. Additional explodedfragmentary view of the components, including the bushings and rollerguides for the rack and pinion assembly 130, are shown in the detailedfragmentary exploded perspective views of FIGS. 20-25.

The rack 132 has a generally U-shaped configuration, as best seen inFIG. 23, including an inside vertically extending leg 123, a centerhorizontal section 124, an outer vertical leg 125, and the horizontallyextending leg 126, which includes the slot 135. The gear teeth 137 areformed in the outer leg 125. In addition to being supported by bushing139, rack 132 is also supported on the side wall 119 of a notch formedin the corner of top 117 of cabinet 110 by a roller bushing assemblyincluding inner and outer bushings 152 and 154, as best seen in FIGS.24-25, which surround a roller 153. Bushings 152 and 154 extend throughslot 127 in leg 123, as best seen in FIGS. 21 and 23, and are rotatablymounted on an axle 155 extending from wall 119. Bushings 152 and 154captively hold the roller 153 to the leg 123 of rack 132 adjacent sidewall 119 while providing guided support with roller 153 engaging asurface 157 (FIGS. 21, 22, 24, and 25) of the cabinet 110. Thus, therack 132 is supported in both vertical and horizontal planes by the axle155 and drive shaft 136 for sliding movement when drive shaft 136 isrotated to which pinion gear 134 is attached by means of a suitable setscrew or the like. This provides a smooth controlled movement of therack 132 for opening and closing the filters 120 between positions shownin FIGS. 15-18, 26, and 27, as shaft 136 is rotated.

FIGS. 26 and 27 are schematic views of the filters 120 using theactuating structure shown in FIGS. 15-25. FIG. 26 shows the relativeposition of both of the filters 120 when fully engaged with the cabinetenclosure for the evaporator for maximum air filtration. FIG. 27 showsthe filters 120 moved to a partially opened position for increasing theairflow through the evaporator to increase the cooling by the airconditioner and decreasing the filtration of air.

FIGS. 28 and 29 illustrate an alternative mounting of the filter movingmechanism shown in detail in FIGS. 15-25 to a pair of door-like filters150 that pivot from the corners of the cabinet enclosure 110 instead ofthe center of the cabinet enclosure 110. In this embodiment, the rackand pinion mechanisms 130 of the prior embodiment are mounted in thecenter at area 158, as shown schematically at 130 in FIG. 29. In thisembodiment, the pivot brackets 146 and associated structure of the priorembodiment are located in the corners as represented by 146 in phantomlines in FIGS. 28 and 29.

FIGS. 30 and 31 illustrate an alternative embodiment in which a singlefilter panel 160 is slideably mounted to move away from the inlet 116 ofcabinet enclosure 110 between the position shown in FIG. 30, in whichthe filter is fully engaged to provide maximum air filtration for thesystem, to a position spaced from the outlet of the cabinet enclosure,allowing the air to bypass the filter in a direction indicated by arrowsA in FIG. 31, with some airflow still being allowed through the filter160. The sliding motion of filter 160 away from the cabinet can beaccomplished with drawer-type slides driven by a rack and pinionmechanism similar to that of elements 130 in the prior embodiments orother conventional slide mechanism which extends between the filter 160and the cabinet enclosure 110.

FIGS. 32 and 33 illustrate an alternative embodiment in which a pair offilters 170 and 172 are movable both away from the cabinet enclosure 110and away from each other, as illustrated in FIG. 33, to provide anairflow path indicated by arrow A in FIG. 33, which extend between thefilters as well as around the edges of the filter. Slide mechanisms,such as drawer slides, can be used for both directions of motion, and arack and pinion drive mechanism similar to that of elements 130 in theprior embodiments can be used to control the movement.

Finally, in FIG. 34 there is shown a filter 180 which can be formed insegments similar to that of a garage door. For such purpose, the panelsof the segmented filter 184 would be coupled to axles with rollersfitted within curved tracks on either side of the cabinet enclosure 110and include a motor coupled to the filter to raise and lower the filtera desired amount for selectively changing the airflow through the filterand cabinet enclosure 110. For all the embodiments describe herein thatprovide for deployment of the filter into or out of the air flow streamit is possible to run the indoor air conditioning unit optimally eitherin air conditioning mode for cooling and dehumidification or withoutcooling and use as an air purification system or combined operationwhere cooling load might be low and the volume of airflow with thefilter in full participation is the optimal user sought condition.

Selective positioning of the dampers (FIGS. 1-14) or filers (FIGS.15-34) can be done manually or with the control of electromechanicalmotor control systems. These systems can be controlled by the user ofthe system by manually moving the filters, with a wireless remotecontrol adjusting a motor connected to the filters, or by a remotesensing and control. The remote sensor/control can evaluate the‘cleanliness’ and desired air temperature and send the settings to thefilter motor for adjustments as desired.

It will become apparent to those skilled in the art that variousmodifications to the preferred embodiment of the invention as describedherein can be made without departing from the spirit or scope of theinvention as defined by the appended claims.

The invention claimed is:
 1. A split air conditioner system including anindoor mounted unit, said indoor unit comprising: a cabinet including anair inlet and an air outlet; an evaporator positioned within saidcabinet; a fan positioned in said cabinet for admitting untreated airinto said cabinet and discharging conditioned air from said outlet ofsaid cabinet; a filter positioned in said cabinet in the flow pathbetween said air inlet and said outlet for filtering air; at least onesecondary air inlet formed in said cabinet at a location between saidfilter and said evaporator; and a damper positioned at said secondaryair inlet for selectively closing and opening said secondary air inletfor selectively providing an airflow path bypassing said filter.
 2. Theair conditioner system as defined in claim 1 wherein said damper is asliding damper.
 3. The air conditioner system as defined in claim 1wherein said damper is a rotary damper.
 4. The air conditioner system asdefined in claim 3 wherein said system includes a centrifugal fan andfurther including baffles mounted in said cabinet to direct air throughsaid blower.
 5. The air conditioner system as defined in claim 4 whereinsaid rotary damper is positioned in said cabinet to engage at least oneof said baffles and is rotatable to three positions for admitting airthrough said secondary air inlet for bypassing said filter, for blockingair from said secondary air inlet, and for allowing air from said airinlet to bypass said evaporator.
 6. The air conditioner system asdefined in claim 5 wherein said filter is a high performance HEPA-likefilter having substantially less pressure drop.
 7. A split airconditioner system including an indoor mounted unit, said indoor unitcomprising: a cabinet; an evaporator positioned within said cabinet; oneof a cross-flow fan, a centrifugal fan, or a muffin-type fan positionedin said cabinet; an air inlet formed in said cabinet for drawinguntreated air into said cabinet to allow said fan to move air from saidinlet through said evaporator; an outlet for discharging air from saidcabinet; one of a filter or a stacked filter positioned in said cabinetin the flow path between said air inlet and said outlet for filteringair; and at least one movable damper positioned in said cabinet forselectively changing the airflow path to selectively bypass said filter.8. The air conditioner system as defined in claim 7 wherein said filteris a high performance HEPA-like filter having substantially lesspressure drop.
 9. An air conditioner for indoor mounting comprising: acabinet for mounting to an indoor surface of a structure; a fan andevaporator positioned within said cabinet; an air inlet formed in saidcabinet for drawing untreated air into said cabinet on a side of saidevaporator to allow said fan to move air from said inlet through saidevaporator; and a pair of parallel spaced-apart air outlets positionedon opposite edges of said cabinet for exhausting treated air into thestructure.
 10. The air conditioner evaporator as defined in claim 9wherein said air outlets are rectangular.
 11. The air conditionerevaporator as defined in claim 10 wherein said air outlets arevertically oriented on opposite sides of said cabinet.
 12. The airconditioner evaporator as defined in claim 10 wherein said air outletsare oriented horizontally at the top and bottom edges of said cabinet.13. The air conditioner evaporator as defined in claim 9 and furtherincluding a filter positioned in said cabinet in the flow path betweensaid air inlet and said pair of outlets for filtering air.
 14. The airconditioner evaporator as defined in claim 13 wherein said cabinetincludes movable dampers for selectively changing the airflow path byeither bypassing said filter or allowing air to flow through saidfilter.
 15. The air conditioner evaporator as defined in claim 14wherein said filter is a high performance filter.
 16. A split airconditioner system including an indoor mounted unit, said indoor unitcomprising: a cabinet having a top, a bottom, a front, and a rearsurface; brackets for mounting said cabinet to an indoor surface of astructure; an evaporator positioned within said cabinet; one of across-flow fan, a centrifugal fan, or a muffin-type fan positioned insaid cabinet; an air inlet in said rear surface of said cabinet foradmitting untreated air into said cabinet to allow said fan or blower tomove air from said inlet through said evaporator; an outlet in saidfront surface of said cabinet for discharging conditioned air from saidcabinet; a filter or a stacked filter system positioned in said cabinetin the flow path between said air inlet and said evaporator forfiltering air; a pair of secondary air inlets formed in said cabinet atthe top and bottom and at a location between said filter and saidevaporator; and a damper positioned at each of said secondary air inletsfor selectively closing and opening said secondary air inlet forselectively providing an airflow path bypassing said filter.
 17. The airconditioner system as defined in claim 16 wherein said stacked filtercomprises one or more of an activated carbon filter, an HAF filter withan ionizer, an antiviral filter, a hydrocarbon filter, a VOC filter, ora dust filter.
 18. The air conditioner system as defined in claim 16wherein said dampers are sliding dampers.
 19. The air conditioner systemas defined in claim 18 wherein said filter is a high performance filter.20. A split air conditioner system including an indoor mounted unit,said indoor unit comprising: a cabinet having a top, a bottom, a front,and a rear surface; brackets for mounting said cabinet to an indoorsurface of a structure; an evaporator positioned within said cabinet; acentrifugal fan positioned in said cabinet; an air inlet in said rearsurface of said cabinet for admitting untreated air into said cabinet toallow said blower to move air from said inlet through said evaporator;an outlet in said front surface of said cabinet for dischargingconditioned air from said cabinet; a filter or a stacked filter systempositioned in said cabinet in the flow path between said air inlet andsaid evaporator for filtering air; a secondary air inlet formed in saidcabinet at the bottom and at a location between said filter and saidevaporator; and a rotary damper positioned at said secondary air inletfor selectively closing and opening said secondary air inlet forselectively providing an airflow path bypassing said filter.
 21. The airconditioner system as defined in claim 20 and further including bafflesmounted in said cabinet to direct air through said centrifugal fan. 22.The air conditioner system as defined in claim 21 wherein said rotarydamper is positioned in said cabinet to engage at least one of saidbaffles and is rotatable to three positions for admitting air throughsaid secondary air inlet for bypassing said filter, for blocking airfrom said secondary air inlet, and for allowing air from said air inletto bypass said evaporator.
 23. The air conditioner system as defined inclaim 22 wherein said filter is a high performance HEPA-like filterhaving substantially less pressure drop.